This invention relates to the art of gunnery and more particularly to certain improvements therein whereby the speed of a projectile fired from a gun can be increased, the projectile can be spin-stabilized and recoil and barrel rise of the gun can be reduced.
Gunpowder was discovered by the Chinese in the middle of the ninth century and was first used in fireworks. There are accounts from the late eleventh century of projectileless guns that hurled flaming gun powder and debris. By the fourteenth century, projectile-firing guns were in use. This was the start of a long evolution that brought about dramatic increases in the reliability of guns and in the speed and accuracy of projectiles.
One of the most important developments in the art of gunnery was rifling. Named from the German word riffeln, to groove, rifling consists of a series of longitudinal spiral grooves on the inner surface of the gun barrel designed to impart a spin to the projectile.
The drill-like spin imparted to the projectile results in several advantages: The gyroscopic spin equalizes irregularities in the projectile's flight, lessening its tendency to depart from a straight line. The spin eliminates the tumbling of the projectile, permitting aerodynamic pointed-nose projectiles to replace the spherical projectiles previously used. The pointed projectiles, having less air resistance, have greater speed and accuracy. The increased speed results in greater range and deeper penetration on impact. The drilling action of the spinning projectile also results in deeper penetration.
The spin-causing rifling, however, also has several disadvantages. The spin is imparted to the projectile through frictional contact with the lands, the nonrelieved portion of the barrel interior. This friction reduces the energy and speed of the bullet. This reduction in energy diminishes the range and penetration of the projectile. The friction between the projectile and the gun barrel also causes the gun barrel to heat up. This poses a hazard to the operator. Often some cumbersome insulation means must be provided for the gun barrel to protect the operator. Moreover, even greater accuracy, of course, is also desired. Finally, the tight fit of the projectile in the gun barrel causes a high pressure build up in the barrel behind the projectile. The release of this pressure produces a recoil than can injure the operator and ruin aim in repeated firing. A related problem is barrel rise: after firing, the barrel of a gun tends to rise. This action ruins aim in repeated firing.
The improvements of this invention comprise a plurality of pressure relief means positioned on an attachment for the barrel of the gun. These pressure relief means are circumferentially spaced to create pressure differentials as the projectile passes through the barrel. These pressure differentials impart a rotary motion or spin to the projectile thereby spin-stabilizing the projectile without frictional contact between the projectile and the gun barrel. It is further a part of this invention to orient these pressure relief means rearwardly and outwardly to reduce recoil and barrel rise in the gun.
The improvements of this invention cause the gun to impart a substantial spin to the projectile and to increase the speed of the projectile without the disadvantages of rifling. This invention reduces the frictional contact between the projectile and the gun barrel thereby eliminating the reduction in the energy of the projectile and the subsequent reduction in projectile speed, range and penetration. Frictional heating of the gun barrel is also reduced.
The improvements of this invention are of simple operation. They are easily and inexpensively incorporated into new guns as well as retrofit to existing guns. Furthermore, they can be incorporated so as to additionally reduce recoil and barrel jump associated with the firing of a gun.